Electronic controlled spiral valve capacity modulation for a portable screw compressor

ABSTRACT

A portable screw compressor that includes a spiral valve configured to be driven by an actuator motor; and an electronic controller coupled to an engine of the portable screw compressor and to the actuator motor. The electronic controller can be configured to, for a compressor pressure of the portable screw compressor exceeding an upper bound of a nominal pressure range, drive the actuator motor to configure the spiral valve to open one or more ports; and for the compressor pressure of the portable screw compressor being lower than a lower bound of the nominal pressure range, drive the actuator motor to configure the spiral valve to close the one or more ports.

BACKGROUND Field

The present disclosure relates to a spiral valve and in particular to electronic controllers configured for spiral valve capacity modulation.

Related Art

Twin screw gas compressors may be known in the related art. In the related art, a screw compressor may include a compressor housing and a motor (for example, a permanent magnet rotor/stator motor) is used to drive one (e.g., a first compression screw) of the two compression screws. The second of the two compression screws may be mechanically coupled to the compression screw that is driven by the motor. The second compression screw may thus be driven by the first compression screw. In the related art, gas may be drawn into the compressor through an inlet, compressed between the two compression screws as they turn, and output through an outlet which is downstream of the gas inlet and the compression screws.

In some related art, one or more bypass ports or valve openings may be formed in the compressor housing or a rotor cowling to allow gas to exit the housing to control or prevent over pressurization or compression along the length of the compression screws. In the related art, the one or more bypass ports or valve openings may be positioned adjacent to a spiral valve that controls the opening and closing of the bypass ports or valve openings by being rotated to a point that allows one or more of the bypass ports to communicate with spiral valve chamber. In the related art, the spiral valve may be pneumatically actuated. In other words, in the related art, the bypass ports or valve openings were opened and closed based on a discharge pressure differential. For example, in some related art systems, a differential pressure of 10 PSI or greater was required to move or position the spiral valve.

However, the pneumatically actuated spiral valves require significant pressure differentials to achieve a full spiral valve stroke. Thus, pneumatically actuated spiral valves may only provide coarse control of the pressure resulting in over capacity, under capacity, and inefficient energy use. Also, the cold temperatures often encountered in the use of portable air compressors are problematic for pneumatic control systems. These systems utilize rubber diaphragms or components to seal the air actuator. The durometer of the rubber components increases as temperatures decrease and can cause leakage and will decrease the effort that the actuator provides. Water trapped in the control system can freeze and reduce or eliminate control until the entire system is warm enough to allow the water to return to vapor.

SUMMARY

Example implementations described herein involve an electronically controlled spiral valve. Through the use of an electronic controller, example implementations can achieve a much more precise movement of the spiral valve to control the capacity of the compressor in a very narrow margin control band (e.g., pressure control band as a function of capacity) over the related art.

Example implementations described herein incorporate an electronic controller configured to issue commands to an actuator motor to move the valve and change the displacement of the compressor. In portable compressors, such example implementation can thereby reduce the torque required to start the compressor and control the capacity of the compressor independent of discharge pressure. Accordingly, such example implementations can change the capacity, torque and horsepower of the compressor to adjust to the needs of the application of the portable compressor.

Cold starting portable compressors can be an issue depending on the application. Internal combustion (IC) engines do not have good cold starting capability, nor do they have good speed-up capabilities during cold start. Through reducing the torque required to accelerate the compressor and opening the spiral valve, example implementations can reduce the torque (e.g., in half) and therefore greatly improve the cold start capability of the compressor.

Further, since the example implementations described herein can change the capacity of the compressor at any given time, for any kind of de-rate strategy or any kind of other strategies that are desired, the example implementations can change the capacity of the compressor to reduce engine load, reduce heat load, and so on in accordance with the desired implementation. Through the combination of an electronic controller with an actuator motor, such controls can be adjusted very precisely, which allows the portable compressor to adapt to very large changes in capacity very quickly and reduce the engine load and fuel consumption.

Aspects of the present disclosure involve a portable screw compressor, which can include a spiral valve configured to be driven by an actuator motor; and an electronic controller coupled to an engine of the portable screw compressor and to the actuator motor, the electronic controller configured to: for a compressor pressure of the portable screw compressor exceeding an upper bound of a nominal pressure range, drive the actuator motor to configure the spiral valve to open one or more ports; and for the compressor pressure of the portable screw compressor being lower than a lower bound of the nominal pressure range, drive the actuator motor to configure the spiral valve to close the one or more ports.

Aspects of the present disclosure involve a non-transitory computer readable medium, storing instructions for execution by an electronic controller connected to an engine in a portable screw compressor comprising a spiral valve configured to be driven by an actuator motor connected to the electronic controller, the instructions involving for a compressor pressure of the portable screw compressor exceeding an upper bound of a nominal pressure range, drive the actuator motor to configure the spiral valve to open one or more ports; and for the compressor pressure of the portable screw compressor being lower than a lower bound of the nominal pressure range, drive the actuator motor to configure the spiral valve to close the one or more ports.

Aspects of the present disclosure involve a system involving, for a compressor pressure of a portable screw compressor exceeding an upper bound of a nominal pressure range, electrically driven means for configuring the spiral valve to open one or more ports; and for the compressor pressure of the portable screw compressor being lower than a lower bound of the nominal pressure range, electrically driven means for configuring the actuator motor to configure the spiral valve to close the one or more ports.

Additional aspects of the present disclosure involve a portable screw compressor equipped with an electronically controlled spiral valve that can be used to produce a variable pressure output, avoid shutdown and/or overheating, modulate capacity by coordinating a variable displacement device and engine speed, and further avoid shutdown caused by any detectable change in operating condition. Such aspects can be facilitated through the use of a programmable electronic controller configured with algorithms as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

A general architecture that implements the various features of the disclosure will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate example implementations of the disclosure and not to limit the scope of the disclosure. Throughout the drawings, reference numbers are reused to indicate correspondence between referenced elements.

FIG. 1 illustrates a perspective view of a screw compressor having a spiral valve structure in accordance with example implementations of the present application.

FIG. 2 illustrates a section view from above of the screw compressor in accordance with an example implementation of the present application.

FIGS. 3A and 3B illustrate section views from each side of the screw compressor in accordance with an example implementation of the present application.

FIG. 4 illustrates support platform for a portable screw compressor configuration mounted to a transportation structure in accordance with example implementations of the present application.

FIG. 5 illustrates an example control system diagram, in accordance with an example implementation.

FIG. 6 illustrates example management information that can be utilized by the electronic controller, in accordance with an example implementation.

FIG. 7 illustrates an example flow diagram for the shutdown instruction set, in accordance with an example implementation.

FIG. 8 illustrates an example flow diagram for the engagement instruction set, in accordance with an example implementation.

FIG. 9 illustrates an example flow diagram for the normal operation instruction set, in accordance with an example implementation.

DETAILED DESCRIPTION

The following detailed description provides further details of the figures and example implementations of the present application. Reference numerals and descriptions of redundant elements between figures are omitted for clarity. Terms used throughout the description are provided as examples and are not intended to be limiting. For example, the use of the term “automatic” may involve fully automatic or semi-automatic implementations involving user or operator control over certain aspects of the implementation, depending on the desired implementation of one of ordinary skill in the art practicing implementations of the present application. Further, sequential terminology, such as “first”, “second”, “third”, etc., may be used in the description and claims simply for labeling purposes and should not be limited to referring to described actions or items occurring in the described sequence. Actions or items may be ordered into a different sequence or may be performed in parallel or dynamically, without departing from the scope of the present application.

As described above, related art screw compressors use a pneumatically actuated spiral valve to control opening and closing of bypass ports or valve openings. However, pneumatically actuated spiral valves may provide only coarse control and may lead to inefficiencies and/or leakage. In order to provide more accurate control of the actuation of the spiral valve, and thereby finer control of the bypass port or valve openings, example implementations may include an electronically actuated spiral valve. For example, an electronic actuator motor coupled to the spiral valve may provide very fine control of the bypass valve opened (e.g., +/−1 PSI pressure control band compared to +/−10 PSI for a pneumatically controlled valve). With finer control of the compressor pressure, energy usage may be optimized by minimizing the gas allowed to flow into the rotors and minimizing gas leakage prior to compression. Additional efficiencies may be achieved by optimizing the bypass port geometry. For example, the number of bypass ports may be maximized, the shutter geometry may be matched to the window geometry, and the bypass port window area may be minimized as described in greater detail below.

By coupling the optimized bypass port geometries with the finer spiral valve control offered by an electric actuator, a number of performance improvements may be achieved. For example, the energy consumed during operation may be reduced while still maintaining consistent pressures and compression volumes due to the finer control of bypass volumes during operation of a screw compressors coupled to electric motors and screw compressors coupled to IC engines.

Further with respect to electric motor implementations (industrial implementations), by being able to dynamically adjust the bypass valve opening within a 1 PSI pressure control band, the in-rush current experienced during start-up or shut down may be reduced, thereby extend operational life of electrical components including the motor, the switch gear and the power distribution components. Similarly, by dynamically adjusting the bypass valve opening in a tight pressure control band, the compression cycle may be controlled to reduce heat loss thereby reducing heat rejection requirements of a compressor cooling system.

Further with respect to IC engines implementations (construction implementations), by being able to dynamically adjust the bypass valve opening within a 1 PSI pressure control band, the start-up torque required may be reduced allowing smoother or easier start-up operations in non-ideal conditions (e.g., cold environment starts, hot environment starts, high-altitude starts, etc.). For example, the bypass ports may be fully opened to reduce the initial compression value to minimize torque demand during start-up. By reducing strain on the IC engine during start-up, starter component (e.g., starter motor, battery, etc.) life may be extended.

Similarly, by being able to dynamically control the compression volume, compression volume may be reduced to prevent or delay engine de-rate or shutdown that may be caused by cold, hot or high-altitude operation conditions.

Additionally, by controlling bypass valve opening dynamically, smoother transitions between idle and full operational speeds may be achieved, and stress on power train components (couplers and mountings) may be reduced. Further, by dynamically reducing compressor load more finely, the engine may be run at lower revolutions per minute (RPM) while reducing stress on the engine and compressor coupler.

FIG. 1 illustrates a perspective view of a screw compressor 100 having a spiral valve structure in accordance with example implementations of the present application. As illustrated, the screw compressor 100 includes a compressor housing 10 that surrounds the compressor inner structure and forms a compression chamber 3 (not shown in FIG. 1, illustrated in FIGS. 2 and 3). The housing 10 may include one or more mounting brackets or feet 2 that support the screw compressor 100 and allow the screw compressor 100 to be secured to a floor or other support platform. For example, the feet 2 may allow the screw compressor 100 to be mounted on a portable support platform or trailer (shown in FIG. 4). The housing 10 also defines a main gas flow intake 26, a main gas flow discharge 28, and one or more bypass gas outlets 215/220. Arrows are provided to illustrate gas flow through the screw compressor 100. Additionally, the compressor housing 10 may allow a drive shaft 15 to pass from the compressor inner structure (illustrated in FIGS. 2 and 3) to the area surrounding the compressor 100.

The drive shaft 15 may be used to mechanically couple the screw compressor 100 to a motor or engine to drive the screw compressor 100. The screw compressor 100 may be driven by an internal-combustion engine (IC-Engine), such as a gasoline engine, a diesel engine, or any other type of engine that might be apparent to a person of ordinary skill in the art. The screw compressor 100 may also be driven by an electric motor, or any type of machine that supplies rotary motive power that might be apparent to a person of ordinary skill in the art.

Further, an actuator module 5 may be attached to the compressor housing 10 and control a spiral valve structure (shown in FIGS. 2 and 3A, 3B) located within the compressor housing. As described below, the actuator module 5 may include an electric motor coupled to a gearbox that is coupled to the spiral valve. Additionally, the actuator module 5 may also include an integrated processor component that may include onboard control logic that controls the actuator module automatically, semi-automatically based partially on a user input or manually based entirely on a user input.

FIG. 2 illustrates a section view from above of the screw compressor 100 in accordance with an example implementation of the present application. The compressor housing 10 forms a compression chamber 3 defining two adjoining bores 6 and 8, each of which includes a screw 7, 9 of the twin screw gas compressor 100, when the unit is assembled and functioning. As illustrated, one of the screws 9 (also known as the drive screw) is mounted on the driven gear 210 and mechanically coupled to shaft 15 by drive gear 205. The motor or engine that drives the screw gas compressor is coupled to shaft 15. The other screw 7 (also known as the driven screw) is driven by drive screw 9. Both screws 7, 9 may each be supported by a bearing group 225, such as roller bearings or any other type of bearing or bushing that might be apparent to a person of ordinary skill in the art.

Further, in some example implementations, one of the screws may have a female lobe configuration, and the other of the screws may have a male lobe configuration. In other words, one of the screws may be a female compressor screw and the other screw may be a male compressor screw that interfaces with the female compressor screw. For example, the drive screw 9 may be a male compression screw and the driven screw 7 may be a female compression screw. As may be apparent to a person of ordinary skill in the art, example implementations of the present application are not limited to this configuration and some example implementations may have an alternative configuration (e.g., the drive screw 9 may be a female compression screw and the driven screw 7 may be a male compression screw).

The end of the housing 10 shown in FIG. 2 is the outlet end 28, and the inlet 26 (in FIG. 1) is not shown in FIG. 2, as it is cutoff in the section view. Gas flow channels 215, 220 may connect each bore 6, 8 with the inlet 26 to allow gas to flow into each bore 6, 8. Each bore 6 and 8 also comprises one or more bypass ports collectively represented by oval 12. The bypass ports 12 a-12 e are formed in bore 6 associated with the driven screw 7. Further, the bypass ports 12 f-12 j are formed in bore 8 associated with the drive screw 9. As shown in FIGS. 3A and 3B discussed below, each bypass port 12 a-12 j shown in FIG. 2 fluidly communicates with a bypass chamber 22 that contains a spiral valve 20 that is rotatable along an axis 24. The length of each barrel 6, 8 associated with the bypass ports 12 a-12 j may be referred to as the bypass window 245.

As described above, the compressor housing 10 has a gas inlet 26 and a gas outlet 28. Within the compressor housing, the gas flow channels 215, 220 provide fluid communication between the inlet 26 and the compression chamber 3. As the screws 7 and 9 turn within the respective bores 6, 8 of the compression chamber 3, gas is compressed inside the compression chamber 3. The compression chamber has a length that runs between compression chamber inlets 230, 235 and a compression chamber outlet end 240. The compressed gas is then output through the gas outlet 28. Arrows illustrate gas flow through the compression chamber 3.

FIGS. 3A and 3B illustrate section views from each side of the screw compressor 100 in accordance with an example implementation of the present application. FIGS. 3A and 3B more clearly shows how the spiral valve 20 functions to regulate compression volume in the compressor. As depicted in FIGS. 1-3B, the compressor housing 10 defines the compression chamber 3, which fluidly communicates with a gas inlet 26 and a gas outlet 28. As the screws 7, 8 turns, gas is compressed inside the compression chamber 3 defined by the radially intersecting bores 6 and 8. The compression chamber 3 has a length that runs between compression chamber inlets 230, 235 and a compression chamber outlet end 240. The compressed gas is then output through the gas outlet 28.

FIG. 3A shows several bypass ports 12 a-12 e formed in the compressor housing 10 adjacent to the bore 6 housing the driven screw 7. A similar structure is illustrated in FIG. 3B showing the opposite side for bypass ports 12 f-12 j formed in the compressor housing 10 adjacent to the bore 8 housing the male compression screw 9. As depicted in FIGS. 3A and 3B the spiral valve 20 includes shutter 335 that selectively either blocks (close) or opens the bypass ports 12 a-12 j, depending on a rotational position of the spiral valve 20. As the spiral valve 20 is turned to a point that allows one or more of the bypass ports 12 a-12 j to fluidly communicate with the spiral valve chamber 22, the effective compression volume of the compression chamber 3 may be reduced due to the smaller compression chamber length. In FIG. 3A, bypass ports 12 c-12 e indicate flow and bypass ports 12 a and 12 b do not indicate flow. With at least one bypass port 12 c-12 e open, the effective compression length of the compression chamber 3 is defined by the distance between the open bypass port closest to compression chamber outlet end 240 and the compression chamber outlet end 240 itself. Similarly, in FIG. 3B, bypass ports 12 h-12 j indicate flow and bypass ports 12 g and 12 h do not indicate flow. With at least one bypass port 12 h-12 j open, the effective compression length of the compression chamber 3 is defined by the distance between the open bypass port closest to the compression chamber outlet end 240 and the compression chamber outlet end 240 itself.

When the effective compression volume is reduced in this manner, toque is reduced, which saves power, increases efficiency, and extends the life of the components of the gas compressor.

The spiral valve 20 is coupled to an actuator module 5 that controls the rotation and position of the shutter 335 of the spiral valve 20. As illustrated, the actuator module 5 includes a motor 325 mechanically coupled to a gearbox 330. The gear box 330 mechanically couples the motor 325 to the spiral valve 20. Thus, a torque from the motor may be transmitted to the shutter 335 of the spiral valve 20 by the gearbox 330 causing the shutter 335 to rotate. The motor 325 may be an electric actuator motor that provides precise control of rotational speed and rotational position of the spiral valve.

The actuator module 5 may be attached to the compressor housing 10 to control a spiral valve structure (shown in FIGS. 2, 3A and 3B) located within the compressor housing. Additionally, the actuator module 5 may also include an integrated processor component that may include onboard control logic that controls the motor 325 module automatically, semi-automatically based partially on a user input or manually based entirely on a user input.

The spiral valve 20 may be rotated (or actuated) along its axis 24 from a fully open position (where all of the bypass ports are open) to a fully closed position (where all of the bypass ports are closed), and all points in between. In FIGS. 3A and 3B, flow is indicated as if the spiral valve 20 was rotated to a point that allowed for a partial bypass of gas from the compression chamber 3 to the bypass chambers 215, 220. Specifically, bypass ports 12 c-12 e and bypass ports 12 h-12 j allow gas to flow from the compression chamber 3 to the bypass chambers 215,220. Gas flow is represented by arrows.

In order to maximize efficiency of the screw compressor 100, the bypass ports 12 a-12 j of FIGS. 2, 3A and 3 b may have specific geometric arrangements according to some example implementations. For example, in order to maximize the number of bypass ports 12 a-12 j within the bypass window 245, several geometric arrangements described below may be implemented either alone or in combination.

In some example implementations, the spacing or distance between adjacent bypass ports 12 a-12 j (e.g., the spacing between a first bypass port and a second bypass port adjacent to the first bypass port) may be within 20% of the minimum spacing permitted based on the manufacturing tolerances associated with the compressor housing 10 manufacturing (e.g., less than 120% of the manufacturing tolerance and greater than or equal to 100% of the manufacturing tolerance). For example, if the compressor housing 10 is formed by a casting process, the casting tolerances may require that the minimum bypass port spacing be at least 5 mm in order to permit proper molten metal flow in the casting mold. If the casting tolerances are 5 mm, then the spacing between adjacent bypass ports may be less than 6 mm (the 5 mm casting tolerance+20%) and greater than or equal to 5 mm (the casting tolerance). Different bypass port spacing parameters may be dictated by different manufacturing tolerances.

In some example implementations, the leading edge of the first bypass port 12 e of the bypass window 245 associated with the female compression screw 7 of the screw compressor 100 may be positioned at or in front (on inlet side) of an apex (greatest diameter) of the first lobe 305 of the female compression screw 7.

Similarly, in some example implementations, the leading edge of the first bypass port 12 j of the bypass window 245 associated with the male compression screw 9 of the screw compressor 100 may be positioned at, but not in front (on inlet side) of an apex (greatest diameter) of the first lobe 340 of the male compression screw 9.

Further, some example implementations may include bypass ports 12 a-12 j positioned to improve matching of the at least one shutter 335 and the bypass window 245. For example, in some example implementations, the bypass ports 12 a-12 e associated with the bore 6 of the female compression screw 7 may be symmetrically positioned with the bypass ports 12 f-12 j associated with the bore 8 of the male compression screw 9. Further, the bypass ports of each chamber (e.g., the bypass ports 12 a-12 e of the bore 6 and the bypass ports 12 f-12 j of the bore 8) may be positioned at the apex (maximum diameter) of lobes of the respective screws 7, 9 that are at equal pressures in the compression cycle.

In some example implementations, the valve shutter 335 may be shaped and positioned to open and close each pair of female and male bypass ports (e.g., 12 a-12 f, 12 b-12 g, 12 c-12 h, 12 d-12 i, 12 e-12 j) simultaneously. In other words, bypass ports 12 a and 12 f open simultaneously, bypass ports 12 b and 12 g open simultaneous, etc.

Alternatively, in some example implementations, the valve shutter 335 may be shaped and positioned to open each pair of female and male bypass ports (e.g., 12 a-12 f, 12 b-12 g, 12 c-12 h, 12 d-12 i, 12 e-12 j) simultaneously. In other words, one of bypass ports 12 e and 12 j may open, followed in sequence by the other of bypass port 12 d and 12 i. Similarly, one of bypass ports 12 e and 12 j may open, followed in sequence by the other of bypass port 12 d and 12 i. Similarly, the other bypass port pairs 12 c-12 h, 12 b-12 g, 12 a-12 f may each open sequentially.

Additionally, some example implementations may include bypass ports 12 a-12 j positioned to minimize the size of the bypass window 245. For example, in some example implementations, the bypass ports 12 a-12 j may be positioned in a bypass window area of the compressor housing 3 that is less than or equal to an area (A_(W)) defined by equation 1 below:

A _(W)=10%±5%*D _(RB) /N _(L)  (Equation 1)

where D_(RB) equals the diameter of the rotor bore of each barrel, and N_(L) equals the number of lobes of the screw associated with each bore. In other words, the bypass window area is no less than 10% and no more than 15% of the rotor bore diameter of each bore (e.g., bores 6 and 8) divided by the number of lobes of the screw associated with each bore (e.g., screws 7 and 9).

Further, in some example implementations, the trailing edge of the last bypass port 12 a of the bypass window 245 may be located at a position of the apex (greatest diameter) of the lobe 310 of the female compression screw 7 that is located in a position where a lowest desired compression volume would be produced. In other words, the volume between the lobe 310 and the chamber outlet end 240 may be associated with lowest desired compression volume of the barrel 6 of the screw compressor 100. Thus, the last bypass port 12 a may be positioned adjacent to the apex of the lobe 310 in some example implementations.

Additionally, in some example implementations, the trailing edge of the last bypass port 12 j of the bypass window 245 may be located at a position of the apex (greatest diameter) of the lobe 345 of the male compression screw 9 that is located in a position where a lowest desired compression volume would be produced. In other words, the volume between the lobe 345 and the chamber outlet end 240 may be associated with lowest desired compression volume of the bore 8 of the screw compressor 100. Thus, the last bypass port 12 f may be positioned adjacent to the apex of the lobe 310 in some example implementations.

Example implementations are not limited to industrial or fixed location configurations and portable configurations may be achieved. FIG. 4 illustrates a support platform 400 for a portable screw compressor configuration mounted to a transportation structure in accordance with example implementations of the present application. As illustrated, the support platform 400 includes a transportation structure 405 and a compressor enclosure 410. The compressor enclosure 410 that surrounds the compressor (not shown in FIG. 4) and may include one or more removable panels 415 that allows access to the compressor.

The transportation structure 405 includes a support frame 430 and a pair of wheels 435 to allow the support platform 400 to be moved. The transportation structure 405 may also include one or more transportation couplers 420 to couple the transportation structure 405 to vehicle to allow movement on the support platform 400. The transportation structure 405 may also include a leveling member 425 to orient the support platform 400 in a level position during operation.

FIG. 5 illustrates an example control system diagram, in accordance with an example implementation. Specifically, FIG. 5 illustrates example components of actuator module 5 as configured to engage with spiral valve 502 and engine 503. Spiral valve 502 can involve the structures and elements as illustrated in FIG. 2 and FIG. 3. Actuator module 5 can include an electronic controller 500, an actuator motor 501 and a sensor array 510.

Electronic controller 500 is configured to transmit electric signals to control the actuator motor 501 and drive the spiral valve 502 in accordance with the desired implementation. Such an electronic controller 500 can be in the form of any physical programmable hardware processor in accordance with the desired implementation, such as but not limited to a central processing unit (CPU), a field programmable gate array (FPGA), a graphics processor unit (GPU) and any other integrated circuit in accordance with the desired implementation. Depending on the desired implementation, the electronic controller 500 may store instructions for various modes of execution as described herein to drive the actuator motor 501.

Such instructions may be stored in the physical programmable hardware processor as described above or can be stored in a memory unit coupled to the physical programmable hardware processor and configured to provide instructions to the electronic controller 500. Such memory units can be in the form of any physical memory in accordance with the desired implementation, such as but not limited to Read Only Memory (ROM), electrically erasable programmable read-only memory (EEPROM), Non-Volatile Random Access Memory (NVRAM), and so on. Depending on the desired implementation, electronic controller 500 can involve an interface (e.g., network interface, Ethernet, serial port, etc.) to connect to an external computer so that the instructions can be updated, or for troubleshooting purposes in accordance with the desired implementation. In another example implementation, the electronic controller 500 can also be connected to an external panel (not illustrated) which involves a display and an input/output (I/O) interface to facilitate manual instructions or provide updates to the instructions stored in the electronic controller 500.

Further, electronic controller 500 is also configured to transmit electric signals to control the engine 503 in accordance with the desired implementation. Example instruction sets are provided in further detail herein.

Actuator motor 501 may be in the form of any actuator motor as known in the art that can be coupled to a gearbox that is coupled to the spiral valve 502 and configured to engage spiral valve 502 based on electronic signal instructions received from electronic controller 500.

Sensor array 510 is configured to receive signals from one or more sensors or from direct measurements of various components of the portable compressor, in accordance with the desired implementation. For example, sensor array 510 can be in the form of a digital signal processor that is connected to mechanical or analog counterparts throughout the portable compressor system and configured to receive mechanical or analog measurements to convert to digital signals for the electronic controller 500. For example, sensor array 510 can be configured to derive RPM of the engine 503 from measuring rotations of the drive shaft and convert the measured rotations to digital signals to provide to the electronic controller 500. Sensor array 510 may also receive other mechanical or electrical inputs related to the spiral valve 502 or any other sensor (e.g., humidity, temperature, etc.) to convert to digital signals for processing by electronic controller 500.

Through the use of a programmable electronic controller 500 as described herein, the example implementations described herein can improve on related art pneumatic systems. Because the spiral valve 502 is electronically controlled, the example implementations can eliminate pneumatic or other control systems that are susceptible to malfunction due to water vapor buildup and freezing or force changes caused by increased durometer that occur at low temperature or internal component corrosion caused by water vapor in high temperature and or humidity environments. Such example implementations further reduce the startup capacity and startup torque of the portable compressor as well as reduce the transitional torque changes. Such reductions can minimize energy consumption and maximize component life of the portable compressor. Additionally, the electronic controller 500 can further improve customer satisfaction by facilitating more consistent gas pressure and capacity.

FIG. 6 illustrates example management information that can be utilized by the electronic controller, in accordance with an example implementation. The management information can include an operation mode for the portable compressor, an instructions set to drive the actuator motor 501/spiral valve 502/engine 503, and a sensor/signal trigger indicating the signals received or the measurements received from sensor array 510 will trigger the indicated operation mode. In an example implementation, operation modes can include, but are not limited to, a shutdown mode to shutdown the portable compressor, an engagement mode to engage the portable compressor, a normal operation mode to maintain a desired compressor pressure within a nominal pressure range in view of particular environments, and so on in accordance with the desired implementation. The management information may be stored in a memory unit of electronic controller 500 or coded into the physical hardware processor of the electronic controller 500 in accordance with a desired implementation. Example of signal triggers can include instructions received from an interface panel or computer connected to the electronic controller, mechanical triggers such as engaging switches, knobs or keys, and so on, depending on the desired implementation. Examples of sensor triggers can include temperature measurements, RPM measurements from the engine 503, pressure measurements from the screw compressor 100, and so on in accordance with the desired implementation.

In example implementations described herein, the spiral valve 502 and the engine 503 of the portable compressor can be controlled independently and with the desired precision by electronic controller 500. Electronic controller 500 can synchronize and time various aspects of the spiral valve 502 and the engine 503 to facilitate the instruction set for a given mode of operation as represented in FIG. 6. Examples of such instruction sets are provided as follows.

FIG. 7 illustrates an example flow diagram for the shutdown instruction set, in accordance with an example implementation. In example implementations, the portable compressor goes through a shutdown strategy which involves opening the ports of the spiral valve 502 as well as engaging the engine 503 to reduce speed. By opening the ports during the shutdown mode of operation, when the engagement mode is initiated to reengage the portable compressor, the spiral valve 502 will already be open, thereby allowing the start of the compressor to be facilitated. Such implementations can be useful in cold temperatures, in which the oil viscosity increases thereby causing the turning torque required to increase.

At 700, the electronic controller 500 invokes the instruction set when a shutdown trigger is received. Such a trigger can involve a temperature received from sensor array 510 exceeding a certain threshold, an instruction to shutdown as received from an interface or as automatically after a period of time, or otherwise in accordance with the desired implementation. At 701, a determination is made as to whether the shutdown was caused by a temperature exceeding a threshold, causing the portable compressor to overheat. If so (Y), then the flow proceeds to 704, otherwise (N), the flow proceeds to 702.

In situations in which the shutdown is not caused by an overheating situation, then the electronic controller 500 will engage the engine 503 to reduce the engine speed until a first speed is met at 702. Such a speed can be set in accordance with the desired implementation and can depend on measurements from sensor array 510 taking into account temperature, altitude, and so on. In an example of a portable compressor that involves an engine running at 2000 RPM at full speed, an example of such a first speed can be 1400 RPM. The reduction of the engine speed before the engagement of the spiral valve 502 allows the portable compressor to maintain the desired power.

At 703, once the first speed is reached, the electronic controller 500 engages the actuator motor 501 to control the ports of the spiral valve 502 to open while continuing to reduce the engine speed to a second speed. The opening of the ports of the spiral valve 502 thereby reduces the torque and the power of the portable compressor. Depending on the desired implementation, the second engine speed is set to a speed above the idle speed of the engine 503 in order to maintain power to the portable compressor. In an example implementation involving a portable compressor with a full power engine speed of 2000 RPM and an idle speed of 800 RPM, the second engine speed can be set to 1000 RPM or otherwise, in accordance with the desired implementation and depending on the measurements received from sensor array 510.

If the shutdown trigger was caused by the temperature exceeding a threshold (Y), then that can be indicative of an overheat condition of the portable compressor. In such a case, at 704, the electronic controller 500 engages the actuator motor 501 to open the ports of the spiral valve 502 while maintaining the engine speed of the engine 503. In portable compressors, lowering the engine speed lowers the fan speed, thereby lowering the cooling capability of the portable compressor. At 705, once the temperature has reduced below a certain threshold, thereby removing the overheat condition, the engine speed can thereby be reduced to the second speed. Thus, example implementations maintain or increase the engine speed while opening the spiral valve 502 to reduce power and torque. Because the engine speed is maintained or increased, the cooling capacity of the portable compressor can thereby be maintained. The capacity and power of the portable compressor can be reduced, which lowers the heat load of the system thereby dropping the temperature while allowing the portable compressor to continue operating at less operation capacity.

Through such example implementations, a complete shutdown of the portable compressor can thereby be avoided through controlling the portable compressor to maintain an idle speed and desired power, as well as facilitating implementations that avoid overheating of the portable compressor and/or shutdown through detectable changes in operating condition (e.g., temperature, humidity, etc.).

Example implementations as described above facilitate an improvement over related art pneumatic systems that do not utilize the electronic controller 500 to control the engine 503 and spiral valve 502 and the spiral valve structures as illustrated in FIGS. 2 and 3. In an example implementation involving a portable compressor with a 2000 RPM full engine speed, by having the electronic controller 500 reduce the speed of engine 503 to 1000 RPM while opening the spiral valve 502 at the times indicated, some proportion of the capacity is reduced by reduction in engine speed, and some proportion is reduced by opening the spiral valve structure, thereby achieving a capacity less than 50%. Related art systems that do not utilize the spiral valve structure as illustrated in FIG. 2 and FIG. 3 have a typical minimum capacity of 50% or 60%, engine speeds as low as 1000 RPM are not maintainable, and a load/unload cycle must be utilized instead, which causes strain to the portable compressor and may damage the cooling system of the portable compressor as a consistent pressure cannot be maintained.

Further, because the example implementations utilize an electronic controller 500 in conjunction with the spiral valve structure of FIGS. 2 and 3 while being configured to engage the engine 503 in a synchronized manner, example implementations described herein can provide an improvement to related art pneumatically controlled systems that independently actuated portable compressor ports and the engine, as both the engine and the ports would be pneumatically engaged and would thereby race to move at the same time, resulting in a mechanical system in which the engine and ports were unsynchronized. However, with the electronic controller 500, example implementations can determine which of the spiral valve and engine is to be engaged first, and at what timing, thereby maintaining the desired timing and synchronization.

FIG. 8 illustrates an example flow diagram for the engagement instruction set, in accordance with an example implementation. The engagement instruction set can be triggered at 800 when it is engaged to turn on or power up from shutdown state, at a preset time, or otherwise in accordance with the desired implementation. At 801, the electronic controller 500 increases the engine speed until a first speed (e.g., high idle speed) is reached. At 802, once the first speed is reached, the electronic controller 500 engages the actuator motor 501 to control the ports of the spiral valve 502 to close. When the spiral valve 502 is completely closed the engine speed of the engine 503 can be increased from the high idle speed to the second speed at 803. Portable compressors that operate at low idle speed with minimum capacity during shutdown mode will have very low torque, hence, the example implementations speed up the engines up to high idle speed before closing the valve to ensure that there is sufficient torque to accelerate the engine 503.

FIG. 9 illustrates an example flow diagram for the normal operation instruction set, in accordance with an example implementation. During normal operation 900 of the portable compressor (e.g., received instructions to induce compression at some pressure, as triggered by a timer schedule, etc.), the electronic controller 500 will control the engine 503 and the spiral valve 502 as it generates a compressor pressure to be within a nominal range of the desired pressure of operation. The desired pressure can be set manually, and the nominal range can be determined by the electronic controller 500 based on altitude measurements, temperature measurements, or other measurements as received from sensor array 510, or set in accordance with any desired implementation. In this manner, the nominal pressure range can be adjusted according to the environment of the portable compressor as measured through sensor array 510. In an example implementation, once a desired compressor pressure is received (e.g., from an interface) by electronic controller 500, the electronic controller can determine an upper and lower bound for the nominal pressure range from the desired compressor pressure (e.g., +/−5%, +/−10%) and an operating engine speed for the engine 503, which can be calculated in accordance with any function in accordance with the desired implementation, or set manually if desired. In an example implementation, if the temperature exceeds a threshold, then the electronic controller 500 may drive the engine speed to be higher than normal operating mode and provide a lower bound of −10% and an upper bound of +5% to ensure that the engine speed is kept higher than normal for cooling purposes.

In example implementations, the electronic controller 500 will command the actuator motor to either close or open the valve based on the measured compressor pressure as received through sensor array 510 and compare it to the desired nominal pressure range. At 901, a determination is made as to whether the compressor pressure is greater than the upper bound of the nominal pressure range. If so (Y), then the electronic controller 500 will engage the actuator motor 501 to control the spiral valve 502 to open at 902, which reduces the air capacity of the system and reduces the compressor pressure. Otherwise (N) the electronic controller 500 proceeds to 903 to determine if the compressor pressure falls below the lower bound of the nominal pressure range. If so (Y), then the electronic controller 500 proceeds to 904 to engage the actuator motor 501 to control the spiral valve 502 to close, which increases the capacity of the compressor, thereby increasing the compressor pressure. Otherwise (N), the electronic controller 500 loops back to 900 to continue monitoring the operation of the portable compressor.

Similarly, electronic controller 500 can also adjust the engine speed of engine 503 at any time during the normal operation 900 while controlling the spiral valve 502. For example, because the electronic controller 500 can engage both the engine 503 and the spiral valve 502 synchronously, the electronic controller 500 can calculate the engine speed that would achieve the lowest RPM possible while maintaining the compressor pressure to be within the nominal pressure range, so that less fuel (e.g., diesel for diesel engine based compressor systems) or energy is consumed to power the portable compressor. Such adjustments can be made in accordance with a function that takes into account environmental conditions (e.g., temperature, altitude, humidity, etc.) and other factors and can be designed in accordance with any desired implementation based on the portable compressor design.

Through using the spiral valve as illustrated in FIGS. 2, 3A, and 3B, the geometry of the valve is such that it can be controlled accurately by the actuator motor and electronic controller, thereby reducing overshoot possibilities. In related art implementations, a small movement in the valve (e.g., 2° rotation) might cause a larger than a 5% capacity change. The subsequent 2° may cause no capacity change and then the next 2° may result in a 10% capacity change, which is neither linear nor proportional. The spiral valve design in FIG. 2 and FIG. 3 allows for a linear and proportionate capacity change, in that each 2° produces roughly 1% capacity change. With the fine adjustments made by the actuator motor and electronic controller, the capacity can thereby be regulated more accurately than in the related art.

Further, the portable screw compressor involving the electronic controller can result in requiring less pressure to obtain full actuation. Pneumatic systems in the related art normally require 10 psi to obtain full actuation, however, through the use of the electronic controller and actuator motor, roughly only 1 psi is required to obtain full actuation of the portable controller. Thus, for a portable compressor system that runs on 100 psi, a pneumatic system would require 110 psi to obtain full actuation, which is a 10% waste of energy, versus the example implementations only requiring 101 psi which is only a 1% waste.

Example implementations can thereby control the air flow of the portable compressor to within 1 psi instead of 10 psi of the pneumatic system of the related art, through the use of the electronic controller accurately coordinating the engine speed with the spiral valve opening.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed.

The foregoing detailed description has set forth various example implementations of the devices and/or processes via the use of diagrams, schematics, and examples. Insofar as such diagrams, schematics, and examples contain one or more functions and/or operations, each function and/or operation within such diagrams, or examples can be implemented, individually and/or collectively, by a wide range of structures. While certain example implementations have been described, these implementations have been presented by way of example only and are not intended to limit the scope of the protection. Indeed, the novel methods and apparatuses described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the devices and systems described herein may be made without departing from the spirit of the protection. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the protection. 

What is claimed:
 1. A portable screw compressor, comprising: a spiral valve configured to be driven by an actuator motor; and an electronic controller coupled to an engine of the portable screw compressor and to the actuator motor, the electronic controller configured to: for a compressor pressure of the portable screw compressor exceeding an upper bound of a nominal pressure range, drive the actuator motor to configure the spiral valve to open one or more ports; and for the compressor pressure of the portable screw compressor being lower than a lower bound of the nominal pressure range, drive the actuator motor to configure the spiral valve to close the one or more ports.
 2. The portable screw compressor of claim 1, wherein the electronic controller is configured to: for receipt of a trigger to shutdown the portable screw compressor: reduce engine speed of the engine until a first speed is reached; and then drive the actuator motor to configure the spiral valve to open the one or more ports.
 3. The portable screw compressor of claim 2, wherein the electronic controller is configured to, for receipt of the trigger to shutdown the portable screw compressor, reduce the engine speed from the first speed to a second speed while driving the actuator motor to configure the spiral valve to open the one or more ports.
 4. The portable screw compressor of claim 1, wherein the electronic controller is configured to: for receipt of a trigger to shutdown the portable screw compressor due to overheating: maintain or increase engine speed of the engine while driving the actuator motor to configure the spiral valve to open the one or more ports; and reduce the engine speed of the engine when a temperature of the portable screw compressor falls below a threshold.
 5. The portable screw compressor of claim 1, wherein the electronic controller is configured to: for receipt of a trigger to engage the portable screw compressor: increase engine speed of the engine until a first speed is reached; and then drive the actuator motor to control the spiral valve to close one or more ports.
 6. The portable screw compressor of claim 5, wherein the electronic controller is configured to, for receipt of a trigger to engage the portable screw compressor, increase the engine speed from the first speed to a second speed while driving the actuator motor to configure the spiral valve to close the one or more ports.
 7. The portable screw compressor of claim 1, further comprising a sensor array configured to provide environmental sensor data to the electronic controller, wherein the electronic controller determines the nominal pressure range and engine speed for the engine from the environmental sensor data.
 8. A non-transitory computer readable medium, storing instructions for execution by an electronic controller connected to an engine in a portable screw compressor comprising a spiral valve configured to be driven by an actuator motor connected to the electronic controller, the instructions comprising: for a compressor pressure of the portable screw compressor exceeding an upper bound of a nominal pressure range, drive the actuator motor to configure the spiral valve to open one or more ports; and for the compressor pressure of the portable screw compressor being lower than a lower bound of the nominal pressure range, drive the actuator motor to configure the spiral valve to close one or more ports.
 9. The non-transitory computer readable medium of claim 8, the instructions further comprising: for receipt of a trigger to shutdown the portable screw compressor: reducing engine speed of the engine until a first speed is reached; and then driving the actuator motor to configure the spiral valve to open one or more ports while possibly reducing the engine speed from the first speed to the second speed.
 10. The non-transitory computer readable medium of claim 9, the instructions further comprising, while driving the actuator motor to configure the spiral valve to open the one or more ports, reducing the engine speed from the first speed to the second speed.
 11. The non-transitory computer readable medium of claim 8, the instructions further comprising: for receipt of a trigger to shutdown the portable screw compressor due to overheating: maintaining or increasing engine speed of the engine while driving the actuator motor to configure the spiral valve to open the one or more ports; and reducing the engine speed of the engine when a temperature of the portable screw compressor falls below a threshold.
 12. The non-transitory computer readable medium of claim 8, the instructions further comprising: for receipt of a trigger to engage the portable screw compressor: increasing engine speed of the engine until a first speed is reached; and then driving the actuator motor to control the spiral valve to close the one or more ports.
 13. The non-transitory computer readable medium of claim 12, wherein the instructions further comprise, while driving the actuator motor to control the spiral valve to close the one or more ports, increasing the engine speed from the first speed to the second speed.
 14. The non-transitory computer readable medium of claim 8, further comprising determining the nominal pressure range and engine speed for the engine from environmental sensor data received from a sensor array. 